From the doc: 'Small, but powerfull monitoring program that secretly captures all keystrokes and all active windows to a text file while running hidden in the background. Logs can be encrypted and automatically emailed to a specified email address. Access to the program is password protected and it can be hidden from the CTRL+ALT+DEL menu. By default it shows a fake speaker icon in the taskbar, but this can also be disabled or changed to a different icon that resembles a commonly used program (icons included), making it totally invisible. Use it to monitor typed URL, chat sessions, e-mails and many other things (passwords ;-)). You can use it for monitoring your children or in your company!'
keyspy.exe